The diagonals of three faces of a rectangular parallelepiped that meet at a single corner measure √5 cm, √10 cm, and √13 cm. What is the volume of this parallelepiped?
SSC CGL 19 जनवरी 2026एक आयताकार समांतर चतुर्भुज के तीन फलकों के विकर्ण, जो एक कोने पर मिलते हैं, क्रमशः √5 सेमी, √10 सेमी और √13 सेमी मापते हैं। इस समांतर चतुर्भुज का आयतन क्या है?
This Question Asked In:
SSC, CGL MAINS 2026
Correct Answer :A - 2 cm³
Detailed Text Solution
Let the edges of the rectangular parallelepiped be a, b and c.
Diagonals of the three faces meeting at a corner are:
√(a² + b²) = √5
√(b² + c²) = √10
√(c² + a²) = √13
Squaring:
a² + b² = 5 ...(1)
b² + c² = 10 ...(2)
c² + a² = 13 ...(3)
Adding (1), (2), (3):
2(a² + b² + c²) = 28
a² + b² + c² = 14
From (1): a² + b² = 5
So c² = 14 − 5 = 9 ⇒ c = 3
From (2): b² + 9 = 10 ⇒ b² = 1 ⇒ b = 1
From (1): a² + 1 = 5 ⇒ a² = 4 ⇒ a = 2
Volume = a × b × c = 2 × 1 × 3 = 6 cm³.
Thus, correct volume is 6 cm³.